Dinner Date
by chasingriver
Summary: Sherlock asks John what he'd like for his birthday and is rather surprised by the answer. John/Sherlock/Mycroft. Warning: sibling incest. This is a one-shot, not related to the Experiments AU.


**A/N:** For Lady Legolas. Many thanks to Deklava for the beta!

**Warning:** sibling incest

* * *

Mycroft was at 221B to discuss Sherlock's latest case.

It wasn't going well.

"What do mean, you haven't worked on it? I told you it was urgent."

"It's boring. Besides, it's painfully obvious. If you weren't too busy filling out paperwork I'm sure you could figure it out yourself."

"Yes, yes. I know. I'm already quite aware that Mr Bergson has been selling state secrets to transvestite prostitutes for months, but we actually need to catch him doing it. I thought you'd be able to help."

"Why on earth would you think that?"

John, sitting quietly in his chair, turned a surprising shade of crimson.

Mycroft smirked.

"Get out, Mycroft."

Mycroft gave his brother a tight smile and got up. "You'll let me know about the case, then?"

Sherlock said nothing and started abusing his violin.

"Very well. John, it was lovely to see you. Happy birthday. I do hope Sherlock got you something nice."

The violin stopped abruptly.

* * *

"John… your birthday."

"It's fine, Sherlock. I didn't expect you to remember."

"I'd like to get you something. What would you like?"

"I'd like to join you and Mycroft for dinner. The two of you seem to schedule them fairly regularly - surely another person wouldn't be an imposition. It is my birthday after all."

There was a very long silence.

Sherlock looked like he was going to say something, and then stopped. There was another long pause.

John smiled. "I'm not stupid, you know."

Sherlock was apparently still clinging to the hope that he was. "Of course the three of us can go out for dinner. I'll phone Mycroft and arrange it."

"No, really. I'm not stupid, Sherlock. I know those aren't dinner dates. Dates, maybe, but I'm guessing you never see the inside of a restaurant. You're not the only one who can deduce things, you know."

There was another long pause. There seemed to be a lot of them.

"It's been going on for years, John. And I'm sure this isn't what you want to hear, but I have no intention of ending it."

"I'm not asking you to."

"Wait. What?"

"I'm not asking you to end it. I'm asking to be allowed in, just once. To watch. I'll understand if either of you say no, but you asked what I want for my birthday, and that's what I want. The only time I ever see you two, you're fighting. I want to see you getting along. Or… whatever this is."

"No, wait. Really? You don't have a problem with this?"

"If I had a problem with it, I would have brought it up months ago when I figured it out. It seems that, for you in particular, my moral code is surprisingly flexible."

"Oh." He bit at his lower lip. "I'll have to discuss this with Mycroft, of course."

"Of course."

"Do you want to participate or just watch?"

"I'll leave that up to the two of you."

Sherlock fished his mobile out of the pocket of his dressing gown and hurriedly sent off a text.

The reply arrived seconds later.

"He'll send a car for us at six." He didn't mention whether John would be involved or not.

* * *

They arrived at Mycroft's spacious flat at half past six.

Mycroft was in a suit, Sherlock was wearing the purple shirt that John adored, and John had made a concession to fashion by _not_ wearing one of his hideous jumpers.

"Good evening Sherlock, John." Mycroft eyed John with curiosity. "I must say, John, I was pleasantly surprised by your choice of birthday gifts. I hope it lives up to your expectations. A drink?"

"Yes, thank you."

Sherlock placed a hand on his shoulder. "You can stop fidgeting, John. I can assure you, you have no reason to be nervous."

John took the glass of scotch from Mycroft and drank a healthy swig before speaking. "I'm not nervous." He had to admit, he even _sounded _nervous. He was slightly terrified.

Sherlock took the glass from John and set it on the side table. He kissed John gently on the lips. "Do you want to participate, or just watch?"

"Just watch."

"Alright. You can always change your mind later, if you want."

Mycroft nodded his head in agreement. "I suggest we retire to the bedroom. It's far more comfortable."

* * *

A pristine dressing gown lay on the bed. "Just in case you change your mind, John…"

Sherlock embraced John from behind as Mycroft started undoing John's shirt. Sherlock's teeth nipping at his ear distracted him from the awkward, if slightly arousing, fact that Mycroft was undressing him. John had a submissive streak a mile wide and Mycroft exuded power. Although he was completely happy in his relationship with Sherlock, he couldn't deny that this excited him.

Sherlock moved down to his neck, nuzzling it and making contented little humming noises as Mycroft worked on his trousers. As Mycroft pulled them down, Sherlock's hand quickly found his erection and started lightly stroking it.

"You still okay with this, love?"

John felt dizzy. "Yes. God, yes. I'll sit over there." Mycroft placed the dressing gown over his shoulders and John made his way to a plushly upholstered chair. It wasn't in the middle of things, but it was close enough that he'd still be able to hear most of what went on. "Really, just pretend I'm not here. That's what I want. I just want to see the two of you. Together."

Neither brother seemed to have a problem with that.

"It's been too long, Sherlock." Mycroft's long, slender fingers fisted Sherlock's hair as he sought out his brother's mouth.

Sherlock started tearing at Mycroft's suit with his characteristic impatience, but Mycroft was just as eager to undress his brother, almost snapping off some of Sherlock's buttons. His quiet reserve was apparently not as pervasive as John had thought.

The electricity between the brothers was almost dangerous in its intensity - they were devouring each other with mouths and hands. Biting kisses and long scrapes of fingernails across skin melded with low, animalistic groans.

Mycroft's mouth stopped biting Sherlock's neck just long enough to hiss, "You needed this, didn't you, little brother? Just like you always need it."

Sherlock just groaned and arched his back as Mycroft's teeth sank back into his neck.

"You can't get enough, can you? Always begging for more." Mycroft stuck two fingers in Sherlock's mouth and let him fellate them. "Look at you, little brother. Such a slut. You just want your mouth filled. I was going to fuck you, but your lips always look so lovely wrapped around my cock." He pulled his fingers out and ran them between Sherlock's arse cheeks. Sherlock writhed and pressed his erection against his brother, longing for more contact. "Tell me what you want, Sherlock."

Sherlock's breathing was ragged as he choked out the words, "Just use me, My. Please."

John felt his gut turn molten. _No wonder Sherlock does this_. Their own sex life was pleasant, normal, and - compared to this - _boring as hell. _He'd happily drop to his own knees in front of Mycroft.

"On the bed. I want your arse tonight, brother-mine. Let's see if John wants to use your mouth so we can stuff you full. You'd like that, wouldn't you?"

"Fuck… yes, My." He scrambled onto the bed. The air reverberated with a loud crack as Mycroft slapped Sherlock's arse. Knelt on the bed, facing John, Sherlock's face was a study in ecstatic pleasure.

"John, will you join us? My little brother would like his mouth filled while I fuck him senseless."

John was on the bed almost before Mycroft could finish the sentence. He knelt in front of Sherlock and roughly pushed the thick head of his cock between his lover's pink lips.

Sherlock groaned with pleasure as he took John into his mouth and started teasing him with his tongue.

Mycroft positioned himself behind Sherlock and slicked up his cock. "What my little brother may not have told you, John…" Mycroft placed the blunt head of it on Sherlock's entrance. "Is that he likes it rough." With that - no more warning and no preparation - he thrust all the way inside his brother.

Sherlock made a sound that should have been somewhere below the human vocal range, and shuddered. After a second, he resumed pleasuring John, and Mycroft started to move.

Each brutal thrust from Mycroft resulted in a deeper thrust onto John's cock. _At this rate, I'm not going to last long. _He reached his hand underneath Sherlock and grabbed his hard, wet cock. He placed his hand over the head of it, and Sherlock made incomprehensible noises as John let Mycroft's thrusts push Sherlock through his fist.

"Not going to last…" John wasn't sure if he was talking to Mycroft or Sherlock. Sherlock was the one with his mouth wrapped around his cock, but Mycroft was clearly in charge.

"Then come down his throat." He slapped Sherlock's arse again. "Pretend it's mine, Sherlock. Pretend I'm spraying your arse and your mouth at the same time."

_That_ thought, apparently, was enough to send Sherlock over the edge, and John felt his hand covered with thick spurts of semen. The look of bliss on Sherlock's face as Mycroft pounded his arse was enough to do John in, and he came deep in Sherlock's throat.

As soon as he pulled out of Sherlock's mouth, the younger Holmes started begging. "Harder, My. Please… I need this. I need you."

And that last sentence sent Mycroft shuddering through his own orgasm, holding his brother tightly as he spent deep inside him.

* * *

The three of them cleaned up in the ridiculously large shower and then lounged on the bed together in dressing gowns.

Sherlock curled up against Mycroft like a cat, and Mycroft absently ran his fingers through Sherlock's hair.

John propped himself up against the headboard next to Sherlock, his legs braced against Sherlock's back. The contact felt good.

The unspoken question hung in the air. _Why?_

Sherlock answered it. "He's the only one who understands what it's like to live in my brain, John. And I'm the only one who understands what it's like to live in his. You've seen how our spoken conversations usually go. This is how we communicate, or at least how we communicate well."

John thought about it for a bit, and nodded. "Thanks."

"Happy birthday, John."


End file.
